JPH06201284A - Streamlined heating tube with fin having constant curvature surface - Google Patents

Abstract

PURPOSE:To provide a streamlined heating tube having constant curvature surface wherein heat transfer rate of the heating tube can be improved. CONSTITUTION:In a heating tube wherein liquid is passed through the tube and gas is passed on the outside thereof, a constant curvature surface 10 is formed on the inner surface of a tube 12 and the external form of the tube has substantially an elliptic shape or is constituted by a curved surface comprising a plurality of curvatures, therefore the external shape is of egg-shape and streamlined. And the tube has a large number of fins 14 on the outside surface thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to CCS (consta).
nt curve surface (constant radius surface) on the inner surface of the heat transfer tube, and the outer shape of the tube is a substantially elliptical shape or a substantially oval shape composed of curved surfaces with a plurality of curvatures. The present invention relates to a heat transfer tube having a large number of fins on its side surface.

[0002]

2. Description of the Related Art For example, in an absorber, a condenser, a regenerator, an evaporator of an absorption refrigerator or an absorption chiller-heater using an aqueous solution of lithium bromide (LiBr) or other heat exchangers, a heat transfer tube is used. In many cases, a liquid is made to flow, and a gas (for example, an air-cooled type, when cooling air is made to flow) is made to flow outside the heat transfer tube.

Conventionally, by making the liquid film thickness on the surface of the heat transfer tube uniform,
To efficiently perform heat exchange, JP-A-63-12399
A two-dimensional curved grooved heat transfer surface as shown in Japanese Patent No. 6 has been proposed.

[0004]

The present invention further improves the heat transfer tube described in JP-A-63-123996, and
It improves the heat transfer coefficient. In the heat transfer when gas passes through the outer surface of the heat transfer tube and liquid passes through the inner surface of the heat transfer tube, the heat transfer coefficient of the outer surface of the tube is extremely low compared to the heat transfer coefficient of the inner surface of the tube, so to increase the surface area, A large number of thin fins are arranged on the outer surface of the heat transfer tube. Therefore, the flow resistance of gas increases, the flow velocity decreases, and the heat transfer coefficient decreases.

In order to prevent this, the present invention reduces the flow resistance of gas by making the cross section of the heat transfer tube main body into a substantially elliptical shape or a substantially oval shape composed of a curved surface having a plurality of curvatures. Prevents the flow velocity from decreasing, and the inner surface of the pipe is CCS
As a (constant radius surface), the surface area on the liquid side is increased, and the surface tension of the liquid thinly extends the liquid to the inner surface of the tube to form a uniform liquid film thickness and improve heat transfer. That is, it is an object of the present invention to provide a heat transfer tube in which the flow resistance of the gas outside the tube is reduced and the film thickness of the liquid in the tube is made constant to improve heat transfer.

[0006]

In order to achieve the above object, a finned streamlined heat transfer tube having a surface of constant radius of curvature according to the present invention allows a liquid to flow through the tube as shown in FIGS. In a heat transfer tube that allows gas to flow outside the tube, the tube 10 has a surface 10 with a constant radius of curvature on the inner surface of the tube 12, and the cross section of the tube outer shape is a substantially elliptical shape or a curved surface having a plurality of curvatures. It is characterized in that it has a substantially streamlined shape of a substantially oval shape and has a large number of fins 14 on the outer surface of the tube. The cross section of the heat transfer tube in this specification is a substantially streamlined shape having a substantially elliptical shape or a substantially oval shape constituted by curved surfaces having a plurality of curvatures as described above. Then, the heat transfer tubes are arranged so that the long axis of the cross section of the heat transfer tube is parallel to the gas flow direction, that is, the angle of attack is equal to the gas flow.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the drawings. However, the shapes of the constituent members described in this embodiment, their relative arrangements, and the like are not intended to limit the scope of the present invention to them only unless otherwise specified, and are merely illustrative examples. Nothing more. FIG. 1 shows the plane of the heat transfer tube 12 of the present invention, and FIG. 2 shows the same front. This heat transfer tube 12 has a constant radius of curvature surface (CCS) 10 on the inner surface, and the outer diameter of the tube is substantially elliptical or substantially oval to form a curved surface having a plurality of curvatures to reduce gas resistance. It is formed in a substantially streamlined shape. In FIG. 1, a heat transfer tube having a substantially elliptical cross section is shown as an example, but another shape, for example, a substantially streamline shape having a substantially oval shape with a curved cross section having a plurality of curvatures You can Further, a large number of fins 14 are attached to the outer surface of the heat transfer tube 12.

FIG. 3 shows a heat transfer tube 12 shown in FIGS. 1 and 2.
Is applied to the absorber 16 and the condenser 18 of the absorption refrigerator or the absorption chiller-heater. The heat transfer tube 12 including the cooling fins 14 is a casing (not shown) of the present case.
It is stored inside. Then, the cooling air flows from the absorber 16 to the condenser 18, as indicated by the arrow. Heat transfer tube 1
2 are staggered so that their major axes are parallel to the cooling air flow, and yet the air inlet 20 is wide and the air outlet 2
As it goes to 2, it becomes gradually narrower. That is, the heat transfer tubes are arranged with different mounting angles so as to have the same angle of attack with respect to the gas flow. In the condenser 18, although not shown, the heat transfer tubes are arranged in a staggered pattern.

Therefore, the flow resistance of the air is reduced, the decrease of the air flow velocity is prevented, and since the inner surface of the heat transfer tube 12 is CCS, the surface area is increased and the surface tension of the liquid makes the liquid thin and uniform. Since it is stretched, heat transfer can be performed very efficiently.

FIG. 4 shows the heat transfer tube 12 shown in FIGS. 1 and 2.
Shows another example in which is applied to the absorber 16 and the condenser 18 of the absorption refrigerator or the absorption chiller-heater. In this example, the main body and the fins are shaped so as to be throttled on the downstream side of the absorber 16, so that the gas flow is made smoother. Reference numeral 24 is a diaphragm.

[0011]

Since the present invention is configured as described above, it has the following effects. (1) The heat transfer tube main body is made to have a substantially elliptical shape or a substantially streamline shape composed of a substantially oval shape formed by a curved surface having a plurality of curvatures so as to reduce the flow resistance of gas, so that the flow velocity of gas is reduced. In addition, the inner surface of the heat transfer tube is formed with a constant radius surface to increase the surface area, and the surface tension of the liquid stretches the liquid thinly and uniformly to the inner surface of the tube, so that the heat transfer coefficient is significantly improved.

[Brief description of drawings]

FIG. 1 is a plan view of a finned streamlined heat transfer tube having a constant radius surface of the present invention.

FIG. 2 is a front view of the same.

FIG. 3 is a perspective view showing an example of use of the heat transfer tube shown in FIG.

FIG. 4 is a plan view showing another example of use of the heat transfer tube shown in FIG.

[Explanation of symbols]

 10 Constant Radius of Curvature Surface 12 Heat Transfer Tube 14 Fin 16 Absorber 18 Condenser 20 Air Inlet 22 Air Outlet

Claims (1)

[Claims] 1. A heat transfer tube in which a liquid is flowed in a tube and a gas is flowed outside the tube, wherein a surface having a constant radius of curvature (10) is provided on an inner surface of the tube (12),
The cross-section of the outer shape of the pipe is a substantially elliptical shape that reduces the resistance of gas or a substantially streamline shape that is a substantially oval shape composed of curved surfaces having a plurality of curvatures, and a large number of fins (14) are provided on the outer surface of the pipe. A finned streamlined heat transfer tube having a constant radius surface.